Fan



June 16, 1936. L, L. DYER 2,044,285

FAN

Filed Nov. 18, 1955 ZiS'E? Z 2997' Patented June 16, 1 933 UNETEQ STAEEg PAT @FFEQE FAN Application November 18, 1935, Serial No. 50,447 In Great Britain December 12, 1934 Claims.

This invention relates to fans, particularly to such as are used for drawing cooling air through the radiators of motor-vehicles or other internalcombustion engines.

The main object of the invention is to provide an improved arrangement of fan blades which will be economical to produce and of great strength, and particularly able to resist the maximum bending stresses which occur near the roots of the blades.

A further object of the invention consists in forming fan blades integrally with one another from a piece of sheet metal by a simple pressing operation. Preferably the uniting portion of the blades has no central hole through it.

According to a further object of the invention, fan blades are formed from a piece of sheet metal by a pressing operation, being integrally united with one another by a portion of the sheet metal r, piece which is bent approximately to semi-tubular shape.

In the accompanying drawing, illustrating one arrangement according to the invention Figure 1 is a view of a flat blank from which a two-bladed fan is to be formed by a pressing operation;

Figure 2 is a view of the fan when formed;

Figure 3 is an elevation thereof; and

Figures 4 to 7 are cross-sections taken on the respective lines (marked with Roman numerals) of Figure 2.

In the construction illustrated, of a two-bladed fan for drawing air through the radiator of a motor-vehicle, the piece of sheet metal is originally a flat strip cut to shape (Figure 1) to provide a central portion l2 which is more or less circular and from which the two blades extend staggered slightly with respect to the longitudinal axis 13 of the strip. This strip is then subjected to a simple pressing operation in which the leading edges l d, I 4 of the blades are left substantially in the plane of the strip, as is also a diameter of the central circular portion, whilst the shaped trailing edges I5, l5 are bent downwardly, to an increasing amount from the tip I6 to the central circular portion. This central portion is bent to be substantially semi-circular in cross-section (Figure 7), thus constituting a semi-tubular part with respect to the longitudinal axis of which the two leading edges M are substantially parallel and on opposite sides. The two opposite segments l1, I! at the ends of a diameter of the central portion at right-angles to the longitudinal axis thereof are outwardly turned to be parallel to the original plane of the strip.

These segments may be drilled (as at l8) for bolts or otherwise adapted for attachment to a driving flange. If desired a disc l9 may be welded to them, this disc providing a diametrical closure to the semi-tubular part.

The maximum width of each blade increases rapidly from the tip up to a distance about onethird of the way along the blade from the tip, the curve of the trailing edge there being approximately an arc of a circle. The width then decreases slightly up to the root, this being brought about partly by the initial shaping of the plain strip (Figure l) and partly by the pressing operation. Y

The metal is not unduly stressed in this way and can be pressed cold; and, owing to the metal not being strained, its strength at the roots of the blades is considerable, so that fracture at these places (where the bending stresses are at a maximum) is prevented.

If desired, the complete structure may be reen- A.

forced in addition, or alternatively, to the disc, as by means of short angle pieces 20, 20 fitted on opposite sides of the semi-tubular part l2 against the out-turned segments 11.

It will be evident that the principles of the invention are particularly applicable to a twobladed fan.

What I claim as my invention and desire to secure by Letters Patent of the United States is:- U

1. A fan comprising, a pair of blades having straight leading edges substantially in alinement and curved trailing edges, a central blade-connecting, semi-tubular portion disposed substantially in the plane of the said blades and integral therewith, the said leading edges of the blades disposed substantially co-planar with the middle of the said semi-tubular portion, and the trailing edges of the blades disposed substantially coplanar with the longitudinal edges of the said semi-tubular portion.

2. A fan comprising, a pair of blades, a central semi-tubular portion integral with and disposed substantially co-planar between said blades, and a disc disposed across the open end of said semitubular portion to reenforce the same against undue stress.

3. A fan comprising, a pair of blades having leading edges and trailing edges, a central semitubular portion integral with and disposed substantially co-planar between said blades, said leading edges being substantially parallel to the longitudinal axis of the said semi-tubular portion and on opposite sides of the same, said trailing edges being curved inwardly to an increasing degree from the outer edge portion to the said semitubular portion to cup the air and direct its flow.

4. A fan comprising, a pair of blades having leading edges and trailing edges, a central semitubular portion integral with and disposed between and substantially co-planar with said blades, said leading edges substantially parallel to the longitudinal axis of the said semi-tubular portion and on opposite sides of the same, said trailing edges being angularly displaced from the longitudinal axis of the said semi-tubular portion and curved inwardly in an increasing degree toward the said semi-tubular portion to cup the air and direct its flow.

5. A fan comprising, a pair of blades havin leading edges and trailing edges, a central semitubular portion integral with and disposed between and substantially co-planar with said blades, said leading edges substantially parallel to the longitudinal axis of the said semi-tubular portion and on opposite sides of the same, said trailing edges being angularly displaced from the longitudinal axis of the said semi-tubular portion and curved inwardly in an increasing degree toward the said semi-tubular portion and a supporting disc adapted to be connected to said semitubular portion to strengthen the same.

LESLIE LEWIS DYER. 

